According to the Center for Disease Control (CDC), over sixty percent of the United States population is overweight, and almost twenty percent are obese, presenting an overwhelming health problem. Moreover, obesity-related conditions cause as many as 280,000 deaths per year, generate $51 billion in annual US healthcare costs, and cause Americans to spend $33 billion per year on weight loss products. For example, one of the principle costs to the healthcare system stems from the co-morbidities associated with obesity. Type-2 diabetes has climbed to 7.3% of the population. Of those persons with Type-2 diabetes, almost half are clinically obese, and two thirds are approaching obese. Other co-morbidities include hypertension, coronary artery disease, hypercholesteremia, sleep apnea and pulmonary hypertension.
Two surgical procedures commonly performed that successfully produce long-term weight loss are the Roux-en-Y gastric bypass and the biliopancreatic diversion with duodenal switch (BPD). Both procedures reduce the size of the stomach plus shorten the effective-length of intestine available for nutrient absorption. However, these are serious surgical procedures with significant side effects, and thus they are reserved for the most morbidly obese.
Other devices to reduce absorption in the small intestines have been proposed (See U.S. Pat. No. 5,820,584 (Crabb), U.S. Pat. No. 5,306,300 (Berry) and U.S. Pat. No. 4,315,509 (Smit)). However, these devices are yet to be successfully implemented.
Examples of gastrointestinal sleeves have been described, which have great promise for treating obesity while minimizing the risks of surgery (See, for example, Meade et al., U.S. Utility application Ser. No. 10/858,851, filed Jun. 1, 2004; the entire teachings of which are incorporated herein by reference). It is important in any intestinal sleeve application to maintain patency of the device. When a sleeve is subjected to retrograde pressure, the sleeve may tend to evert (i.e., fold inward upon itself). Such eversions are undesirable and may lead to blockage, sleeve damage, and related complications. Thus, further improvements are desired to more fully realize the advantages which can be provided by gastrointestinal sleeves while minimizing any risk of complications.